The Uzbeks, during the reign of Tahmāsp, attacked the eastern provinces of the kingdom five times, and the Ottomans under Suleymān I invaded Iran four times. Decentralized control over Uzbek forces was largely responsible for the inability of the Uzbeks to make territorial inroads into Khorasan. Putting aside internal dissension, the Safavid nobles responded to a threat to Herat in 1528 by riding eastward with Tahmāsp (then 17) and soundly defeating the numerically superior forces of the Uzbeks at Jām. The victory resulted at least in part from Safavid use of firearms, which they had been acquiring and drilling with since Chaldiran.